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RFC · NetworkingStandard explained

RFC 791: IPv4: The Internet Protocol

Summary

RFC 791 describes IPv4 datagrams, addressing, fragmentation and connectionless forwarding between networks. A minimal core protocol made an internet of very different networks possible. Connectionless forwarding deliberately moves reliability to the endpoints.

Ideas

  • Routers forward datagrams independently of each other.
  • TTL limits endless forwarding loops.
  • Fragmentation adapts packets to smaller transmission links.

Facts

  • RFC 791 replaces RFC 760.

Remarks

  • RFC 791 has the status “Internet Standard”; current errata and successor documents should also be checked.

Recommendations

  • Avoid IPv4 fragmentation through proper MTU discovery.
  • Treat IPv4 today together with its later updates.

References

Read the RFC at the RFC Editor

Search the Web Archive

RFC · 1997

RFC 2131: DHCP: Automatic IPv4 configuration

RFC 2131 describes DHCP for dynamic addresses and other network parameters from centrally managed pools. Automation simplifies operations and makes the DHCP service critical for network access. Leases connect identity, time and address management.

RFC · 1996

RFC 1918: Private IPv4 address spaces

RFC 1918 reserves three IPv4 ranges for internal networks that are not routed globally. Private addresses extended the life of IPv4 but created lasting NAT and merger problems. Non-global addressing is no substitute for access control.

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